Conventionally, near field communication has been used for transmission/reception of information. In near field communication, transmission/reception of information is performed by bringing a tag reader and a tag into proximity to each other. Patent Literatures 1 to 8 below each disclose a near field communication technique. For example, Patent Literature 1 discloses a technique for activating a tag reader in a case where a touch sensor detects presence of a tag. This technique is intended to reduce electric power consumption. Further, Patent Literature 2 discloses a display device including a plurality of tags.